The Manuel Primary was a wooden aircraft built around an open, vertical, tapered girder with a horizontal upper member and a lower one shaped at the front into a shallow keel.
The keel projected forward of the foremost vertical member and carried the pilot's seat on its upper edge.
The thick-profile wing was attached to the upper part of the girder and was straight edged with constant chord apart from the angled tips of the ailerons.
Extensions of two of the forward girder cross-pieces formed a triangular structure over the wing which acted as a king post for a pair of landing wires.
Flying wires from the keel and the upper member about halfway to the rear of the girder carried the lifting loads on the wing.